Confused

[Kingman11]

Okay so last week we bought a 1997 Seadoo speedster, starts easy the normal cold start up smoke of a 2 stroke, cleaned up really nice, Took it out on the lake the next day with 4 of us and some gear we pegged at 45 pretty good for being over the weight! Put 26 miles on the lake then loaded and went home, that was last week, we are going out tommrow and we checked the compression a few hours ago it was 120,120,120,90? The boat starts easy,doesnt smoke except for the average cold start smoke, Runs perfectly in the water. What could be the problem here? The compression tester?

 

[Dr Honda]

Welcome.

You are right... 45 mph for an overloaded speedster is good. They normally get into the low 50's with 2 people in them.

I would be pointing my finger at the gauge since it's running well. With a seadoo... normally, under 120 psi, and they don't run very well. (150 psi would be a fresh engine)

Find a new gauge, and try it again. Also... the part that threads into the engine... make sure there is a good O-ring on it. I've seen people pull apart a perfectly good engine because the seals in the compression gauge was bad.

Finally... when doing the compression check... make sure the engine is cold... and hold the throttle open. Oh... and since you are new to SeaDoo... if you look on the MAG cover, you will see 2 metal posts, with an orange insulator. Those are there to ground your spark plug wires when working on your engine. It's important to ground the wires when working on the engine so you don't roast the ignition coil.

 

[Kingman11]

Bought a new compression tester and still at 120,120,120,100 now though... Took it out by myself and is still running great hit close to 53 and the water got choppy, Im confused because everyone says 120 and it will hardly run... Whats the problem or are they one?

 

[Dr Honda]

I'm having a hard time with it myself. Did you do the test with the throttles open?

All I can say is to hook you gauge to an air compressor to verify it.

IF... you have that low of compression... you should change the rings before you get a melt-down.

 

[bigJake]

I'm having a hard time with it myself. Did you do the test with the throttles open?

All I can say is to hook you gauge to an air compressor to verify it.

IF... you have that low of compression... you should change the rings before you get a melt-down.

just a thought - if he put a couple shots of oil in the low cylinder before testing the compression and he got a higher reading would that help to verify that the gauge is ok and the cylinder really is low?

 

[Dr Honda]

just a thought - if he put a couple shots of oil in the low cylinder before testing the compression and he got a higher reading would that help to verify that the gauge is ok and the cylinder really is low?

Oil will seal up bad rings. I guess if you get a MUCH higher reading... it would verify that the rings are bad. If you only get a slightly better reading... then I would point my finger at the gauge again.

 

[Kingman11]

No never did it with cars so didnt with the boat.... Could it make that big of a diff?